The nice thing about these little things is that they can do what other generators simply cannot. My handheld smoke generator is the most versatile unit I have. Plainly put with this unit, if it can be consumed, it can be smoked, indoors. You name it, a layer of smoke can be applied in mere minutes. It is primarily for cold smoking, of course, and it cannot replace the deep penetration that longer hot or cold smoking creates, but it can give a good smoke flavor and aroma to anything.
I'm in 100% agreement with you Tom. I don't know which handheld units you're referring to, but I've had the Smoking Gun from PolyScience for around 3 years, and it's frequently in use . Primarily for items where it wouldn't be practical to start up either the hot or cold smoker.
Most recently, it was for a couple dozen fresh oysters that were used in Thanksgiving's oyster dressing. Put the oysters in a Ziploc freezer bag, closed it except for a small opening to insert the gun's hose, hit it with smoke for about 15 seconds, then sealed the bag for 20 minutes. Repeated the process a couple more times over an hour. The result produced an outstanding dressing.
I did the same a couple weeks prior with a couple Chilean sea bass fillets my wife brought home, and prior to that, the same with some large sea scallops. Whenever I make gumbo or jambalaya with chicken, the gun comes out. A while back, I made up a large batch of Bloody Mary mix and inserted the hose into the mix with great results. I also often use it with prepared vegetables when making soups or stews.
Again, when the mass of the item(s) you want to apply smoke to is not large, and it's not practical to start up the traditional smokers, the gun, for me, is the way to go.